Filter and press roll therefor



Dec. 15, 1931. A. J. HA-UG 1,836,243

FILTER AND PRESS ROLL THEREFOR Filed Dec. 20, 1928 2 Sheets-Sheet 1 Dec.15, 1931. I A. .1. HAUG FILTER AND PRESS ROLL THEREFOR Filed Dec. 20,1928 2 Sheets-Sheet 2 1710871702: if r Patented Pee. 15, 1931 ANTON J.HAUG, OF NASHUA, NEW HAMPSHIRE rmrna AND rnnss Rom. THEREFOR Applicationfiled December 20, 1928. Serial No. 827,891.

This invention relates to filters and to paper making and isparticularly concerned with expressing water from the pulp sheet on thepaper making wire or other support for the sheet.

It is common practice to use press rolls which bear on the wet papersheet while it is on the wire to express water from the sheet throughthe paper making wire. These rolls, known as dandy rolls, are hollow andhave a perforated periphery, commonly consisting of a wire screen. Inuse some of the water which is expressed from the wet paper sheet passesthrough the periphery of the roll into the interior thereof and issubsequently discharged again upon the partly dry paper sheet, thuspartially destroying the object of the roll.

Furthermore, the roll especially When operating on short fibred stockhas a tendency to detach some of the short pulp fibres from the papersheet, thereby impairing the quality of the sheet.

An object of the present invention is the provision of a paper makingmachine and a roll therefor which will operate to express water from thepaper sheet through the paper making wire without picking up andsubsequently discharging water onto the partly dried sheet and withoutdetaching pulp fibres from the sheet and also without disturbing thepaper sheet or forming a wave thereon, just in front of the line ofcontact between the roll and the paper sheet.

I have found that I, can obtain highly satisfactory results with a roll,the sheet-engaging surface of which is imperforate but has small pocketstherein in which some of the Water in the wet paper sheet can collectbut from which pockets the water can not escape at the time they are atthe paper sheet; and this constitutes a further object of the invention.

Another object of the invention is the provision of a press roll for apaper making'machine which has an imperforate cylindrical wall and hasdetachable means on said wall that forms isolated pockets that are openin the sheet-engaging face of theroll.

Another object of the invention is generalvention.

Fig. 2 is a sectional elevation machine of Fig. 1.

Fig. 3 is a section along line 3-3 of Fig. 2.

Fig. 4 is a front elevation partly broken away of the dandy or pressroll of Figs. 2 and 3.

Fig. 5 is an enlarged sectional detail of the imperforate cylindricalwall of the press roll and illustrating the pocket-forming wire screenthereon.

Fig. 6 is an enlarged plan detail of the periphery of the press rollillustrating the pockets in the face thereof. 1

Fig. 7 is a'view similar to Fig. 5 but illustrating a modified method offorming the pockets in the sheet-engaging face of the roll, the pocketsbeing shown in exaggerated size.

through the Fig 8 is a plan detail of a portion of the surface of theroll constructed'as illustrated in Fig. 7.

Fig. 9 is a section similar to Fig. 5 but illustrating a furthermodified construction of the roll.

Fig 10 is a plan detail of a portion of the surface of the roll of Fig9, the size of the pockets being magnified.

The invention for simplicity is here shown as embodied in a paper makingmachine of thecylinder type although it is not limited in itsapplication to this type. The machine comprises a tank 12 having acylinder compartment 14 in which a paper making cylinder 16 of anysuitable construction is rotatable. A couch roll 18 is located above andin engagement with the cylinder for the purpose of taking off the papersheet from the paper making wire on the cylinder above the level of thepulp stock in the compartment 14.

A press or dandy roll 20 is located above the paper making cylinder andis in engagement with the paper or pulp-sheet thereon above the level ofthe pulp stock and in front of the couch roll for the purpose ofexpressing water from the wet paper sheet and for forcing the waterthrough the perforate paper making cylinder into the interior thereof.The press roll comprises a cylinder, see especially Fig. 4, which is ofa suitable diameter and length and, in accordance with this invention,is imperforate. End plates 24 are located within the ends of saidcylinder and are fixed thereto. Shafts 26 are fixed in hubs 28 of saidend plates and form rotatable bearing supports for the roll.

The roll is held in pressure applying rolling engagement with the papersheet on the cylinder by its own weight which can be enhanced orpartially oflfset b a suitable counterwei ht. To this end, t e shafts 26are rotatab e in bearing blocks 30, one of which is shown in Fig. 2,that are vertically slidable between spaced upstanding guides 32 of theframe 12.

A lever 34 is located above the bearing block and is pivoted thereto bya pin 36. A counterweight 38 is slidable on said lever. Said lever canalso be pivotally connected with either one of the arms 33 by means of apivot pin which can be located in either one of the pivot holes 40 and42. When the lever is connected to one of said guides, the pressure ofthe roller is increased by the weight of the counterweight 38 and theleverage thereof. When the lever is connected to the other guide, thepressure of the roll on the paper sheet is diminished by the weight ofthe counterweight and the leverage thereof. The construction thusdescribed is the same at both ends of the press rolls.

In accordance with this invention} the outer or sheet-engagingimperforate periphery of the roll is provided with a plurality of smallpockets which are excluded or substantially excluded from communicationwith each other and are each open only at the sheet-engaging peripheryof the roll. The pockets can be made in any suitable manner. In Figs. 7and 8 I have shown the periphery of the roll formed with a plurality ofsmall pockets 43 which are drilled into the roll from the outerperiphery thereof. This method of forming the pockets is expensive,however, and I prefer to form the pockets as shown in Figs. 6 or 9. InFig. 6, the pockets are formed by wrapping awire screen 44 upon theouter periphery of the roll and securing the screen detachably thereto.The open spaces between the warp and filler strands of the wire screenform pockets 46 which excellently fulfill the requirements of myinvention The wire screen can be of any suitable mesh. A twenty meshscreen is satisfactory. A forty and also a sixty mesh screen will givegood results.

The characteristic feature of the pockets is that they are so small thatthey collect and retain only sufficient water'to lubricate the surfaceof the roll, to prevent the web from adhering to it. The pockets are notintended to abstract any material amount of water from the web.

In Fig. 9 the pockets are formed by securing a closely perforated plate48 detachably about the periphery of the roll. In this case, theperforations 50 of the plate form the pockets and the inner openings ofthe perforations are closed by the cylinder.

With such constructions, it is apparent that water can not pass throughthe pocketed imperforate cylinder and be subsequently deposited on thepartially dried paper sheet aslis the case with the usual perforatepress re 1.

I find also that a press roll constructed as above described, does notpick up any material amount of short fibres from the paper sheet, thereason apparently being that the small perforations fill with Water justbefore the roll comes in pressure contact with the sheet and since thewater can not escape through the roll, there is no force that detachesthe short fibres from the sheet and attaches them onto the roll ordeposits them in the perforations thereof.

The pocketed imperforate roll also prevents the formation of a thickenedmass or wave of wet pulp stock immediately ahead of its point of contactwith the paper sheet, as is the case with a solid imperforate press rollsince the pockets, being empty before they engage. the roll, serve toreceive the water on the sheet that would otherwise be pushed ahead ofthe roll.

The cylinder machine here illustrated in connection with this inventionis described and claimed in my copending application Serial No. 327 ,944filed December 22, 1928.

I claim:

1. In a paper making machine, the combination of a paper making wire onwhich the paper sheet is made, and a press roll that is in directengagement with the wet paper sheet on the wire for expressing water outof the wet paper sheet and through the wire having an imperforatesheet-engaging face which is provided with closely disposed pocketswhich are of small extent axially and peripherally of the roll and areisolated from each other and are open only at the sheetengaging surfaceof the roll and which are so small that they retain therein water whichprevents the adherency of the sheet to the roll.

2. In a paper making machine, the combination of a paper making wire onwhich the paper sheet is made, and a press roll that is in directengagement with the wet paper sheet on the wire for expressing waterfrom the paper sheet through said wire having an imperforate peripherythat has small waterretaining pockets therein that are open onllly atthe sheet-engaging periphery of the ro 3. In a paper making machine, thecombi-- bears upon the wet pulp sheet nation of a movable surface thatsupports a wet pulp sheet, and a press roll bearing directly on the pulsheet to express water therefrom througli said movable surface having awater-imfierforate porous sheetengaging surface t e pores of which areisolated from each other and are open only at said surface of the rolland are sufficiently small to retain water therein which prevents theadherency of said sheet to the roll.

4. In a paper making machine, the combination of a perforate surfacewhich supports a wet paper sheet, and a press roll bearing directly onthe paper sheet to express water therefrom through said perforatesurface, said roll having an imperforate sheet-engaging face formed withsmall isolated water-retaining pockets therein that are closed bothaxially and circumferentially of the roll and are open only at saidsheetengaging face of said roll.

5. In a paper making machine, the combination of a paper making wirewhich supports a wet paper web, and a press roll bearing directly onsaid web to express water therefrom, said roll having a smoothimperforate cylindrical wall and a sheet having isolated perforationsencircling and carried by said wall in direct contact therewith andhaving a smooth surface that directly engages said wet pulp web, saidcylindrical wall forming a closure for the bottoms of the perforationsin said sheet, so that they are open only at the sheet, and theperforations being so small as to retain water therein.

6. In a paper making machine, the combination of a paper making wirewhich supports a wet paper web, and a press roll hearing directly on thewet paper web having an imperforate cylindrical wall, and a sheet havingsmall isolated perforations encircling said wall on the outer facethereof having 1ts perforations closed at said wall.

7. In a paper making machine, the combination of a movable surface whichsupports a wet pulp sheet, and a press roll which to express watertherefrom, said roll having an imperforate cylindrical wall and having awire screen which engages on its outer face and which is adapted to bearupon the wet pulp sheet, said screen having a mesh which is suflicientlysmall to retain water therein, and said wall forming a closure whichprevents water from passing through said screen.

8. A press roll which is adapted to bear directly upon a' wet papersheet to express water therefrom having a smooth imperforatesheet-engaging wall that has small water-retaining pockets in itssheet-engaging face that are open only at said sheet engaging face, thepockets being sufficiently close together to provide the sheet-engagingface of said roll with a water-film that prevents the adherence of saidsheet to said roll.

9. A press roll which is adapted to bear directly upon a wet paper webto express Water therefrom having a smooth im erforate cylindrical walland, a cylindrical sheet which bears directly on the outer face of saidwall and which has small, closel spaced, water-retaining perforationstherein which are closed at the bottom by said wall.

. 10. A press roll adapted to bear upon a Wet papeu sheet to expresswater therefrom having a smooth imperforate cylindrical wall and a wirescreen on and in direct engagement with the smooth outer face of saidwall, the wall thus sealing the openings in said screen and preventingwater from passing therethroug 11. In a paper makin machine, thecombination of a paper ma 'ng wire on which the paper sheet is made, anda press roll which directly engages the paper sheet and expresses watertherefrom through said wire, said press roll having aplurality ofisolated pockets in its sheet-engaging surface which are open only atthe surface of the roll and are so small and so closely spaced that theretain on the roll surface, and between t e surface and the sheet, filmsof water which are sufiiciently peripherally continuous to to the roll.

In testimony whereof, I have signed my name to this specification.

ANTON J. 'HAUG.

prevent the adhering of the sheet the bottom by I

